Tampon sales in the UK have decreased by around a fifth since 2012, new figures show.
Research from Kantar Worldwide suggests 23.2 million packs were sold in the year ending October 2016.
In the same timeframe in 2012, more than 29.4 million boxes of tampons were bought in the UK.
A million fewer packets of sanitary towels were also sold last year, compared to 2012, with total pack sales of 84.5 million.
In terms of cash, £236m was spent in 2012 on tampons, liners and sanitary towels.
Tampon sales account for £55.6m of that figure.
That compares to £221m in total and £43m on tampons in 2016.
The average price of a tampon has remained unchanged over these years.
Around half of the spending drop could be because shoppers left the tampon market completely, Lauren Feltham from Kantar Worldwide said.
This could be because more women are using contraceptives which either lighten their period, or stop it all together.
Long-acting reversible contraception (LARC) is slowly growing in popularity, Public Health England reports.
Both the injection and the implant can affect menstruation and stop it happening altogether.
Other factors behind the decline could be that as the UK population ages, more women will have gone through the menopause and therefore not experience a monthly period.